Apparatus for the destacking of sheets especially folded sheets adapted to receive an insert

ABSTRACT

An apparatus for the destacking of folded sheets to enable them to receive an insert in the formation of signatures, book blocks and the like which includes a drum rotatable beneath the stack and provided with a plurality of angularly equispaced pickup rolls. The pickup rolls are rotatable in a sense opposite the sense of rotation of the drum and are provided with sheetengaging arrangements, e.g. suction apertures, adapted to entrain the folded edge of the sheet at the bottom of the stack as the drum rotates each roll therepast. At a location angularly spaced from the stack in the direction of rotation of the drum and sufficient to permit the sheet-entraining roll to rotate through about one revolution, a gripper lever draws the folded edge of the sheet away from the drum on a forward stroke and, upon a return stroke, feeds the folded sheet, with its folded edge rearwardly in the direction of movement of the sheet, between the belts of a conveyor which delivers the folded sheets to a foldspreading device.

United States Patent [72] Inventor Rudolf Hepp Schmidt-Ott-Strasse, 7a, Berlin 41. Germany [211 App]. No. 820,889

[22] Filed May 1, 1969 [45] Patented Jan. S, 1971 [32] Priority May 10, 1968 [33] Germany Continuation-impart of application Ser. No. 690,445, Dec. 14, 1967.

754] APPARATUS FOR THE DESTACKING OF SHEETS ESPECIALLY FOLDED SHEETS ADAPTED TO FOREIGN PATENTS 696,667 10/1940 Germany Primary Examiner-Even C. Blunk Assistant Examiner-Douglas D. Watts Altorney- Karl F. Ross ble beneath the stack and provided with a plurality of angularly equispaced pickup rolls. The pickup rolls are rotatable in a sense opposite the sense of rotation of the drum and are provided with sheet-engaging arrangements, e.g. suction apertures, adapted to entrain the folded edge of the sheet at the bottom of the stack as the drum rotates each'roll therepast. At a location angularly spaced from the stack in the direction of rotation of the drum and sufficient to permit the sheet-entraining roll to rotate through about one revolution, a gripper lever draws the folded edge of the sheet away from the drum on a forward stroke and, upon a return stroke, feeds the folded sheet, with its folded edge rearwardly in the direction of movement of the sheet, between the belts of a conveyor which delivers the folded sheets to a fold-spreading device.

PATENTEBJAN 5197i 3552740 SHEET20F2 Rudolf Hepp INVENTOR.

Attorney This application is a continuation-in-part of m y applicatio'n Ser. No. 690,445,filed Dec. l4, 1967'. A

My present invention relates to an. apparatus or device for the destacking of sheets and, more particularly, for the removal of successive folded sheets'from the bottom of a stack thereof in order to enable these sheets to be spread or opened and thereby receive an insert.

lnmy application Ser. No. 690,445,-filed Dec. 14, 1967, l have described improvements in a method of and a device for opening out sheets of paper inorder toen'able them to receive inserts. The inserts may be introduced. between the spread leaves of the folded sheet by the me ans'described in my application Ser. No. 690,444, also filed'DecI, 14, 1967, now US. Pat. No. 3522942 and entitled Means For Putting inserts lnto Printed Publication." 7 f In the printing art, it is common to form-stacks of folded sheets in the form of signatures or individual sheets which are to constitute signatures, book'blocks,.-brochures, prospectuses, pamphlets and thelike, consistingof at least one folded sheet and one or more inserts (which may also be folded sheets) received between the leaves thereof. In application Ser. No. 690,445, mentioned above,-'l have pointed out that it is 'commonpractice to work on individual folded sheets whereby the sheets of a particular brochure or book block are 7 placed one on top of another in the correct sequence to form a chain which feeds the individual sheets to a machine in which the sheetsare combined and made up to form the b ro'chure or book block concerned.

' As described in this latter application, the sheets may be folded offcenter so that, at the edge of a sheet side or leaf lying opposite the fold edge or ridge, there'isprovided a forefold, i.e. a projection. When the sheet is'opened outwardly, the

forefold may be gripped by a tool anddrawn away from the gaged, to a gripper tool which seizes the folded edge of the sheet and holds it firmly. On further movement of the-cylinder support, .the sheet is wound off from the gripper roller and is thereby released by the feeder. 1

Prior to the aforementioned applications, it had been proposed by myself and others to destackfolded sheets by engaging them at their folded edges a'ndthento shift these sheets in such manner that spreading of the leaves thereof to receive an, insert is made possible. In priorart-or conventional systems of this type, relatively complex arrangements are required to change the direction of movement of the folded sheet'from movement in which the fold is the leading edge to a movement in which the free edges of the leads-( rer:'note from the fold) are constituted as the leading edge whereas the fold becomes the trailing edge. The systems used for this-purpose have become relatively complex and occupy considerable space while being often inaccurate.

sheet side without the forefold and released onto a conveyor chain. In conventional devices for opening out sheets of paper of this typed, having a'forefold',. 'the individual sheets are placed in a feeder from which they are singly ejected with the forefold lying forwardly (with respect to the direction of movement of the sheets) and are conveyed to tools which are designed to open out the folded sheet and grip the forefold.

In application Ser. No. 690,445, it is further pointed out that such systems are disadvantageousj' in accordance with the system of this application, the individual sheets displaced on their path from the feeder to the opening-out tools arety of guard rails with the stack sheets of the fold stack resting against the guard rails. The cylinder support revolves counter-- clockwise about its central axis 'in one sense while three' gripper rolls or rollers are arranged in the cylinder supportand revolve clockwise, i.e. in the opposite sense, counter to the direction of rotation of the cylinder support. The gripper rollers are each equipped with a suctioner. When the cylinder support carries one of the gripper rollers below the folded edge of the bottommost sheet of the stack, the gripper roller engages with its suctioner the fold-ridge or edge of the lower sheet. On further movement of the cylinder support counterclockwise and on simultaneous rotation of the gripper roller in the clockwise sense, the gripped sheet is wound up upon the gripper roller. When the gripper roller reaches its'discharge position, the suctioner frees the sheetwhich has been enlt is, therefore, the principal object of the presentinvention to extend the principles originally set forth in my application SersNo. 690,445 and provide an improved apparatus for the destacking and feeding of folded'sheets' to enable them to receive inserts. .f

Yet another object of this invention is the provision of an improved destacking apparatus for folded sheets which isr'elatively simple and free from problems of breakdown and the like and yet which can effect a change in the direction of feed of a folded, sheet or signature.

' l have found that these objects can be obtained in a relatively simple apparatus in accordance with thepresent invention,

for the destacking of sheets, preferable folded sheets, adapted to be drawn from a stack thereof. According to the principles- -of the present invention, a destacking or feeder drum. or 4 cylinder support, rotatable in one sense andzprovid'ed with a Accordingto a key feature of this-invention, the gripper.

roller draws the released sheet away from the discharge station during its forward stroke, i.e.the sheet continues its displacement with its engaged edge moving forwardly with respect to the direction of displacement. On its return stroke, however, the gripper tool or arm, which remains engaged with the edge originally seized thereby, thrusts'the sheet in the op posite direction whereby the seized edge is transformed into the trailing edgeand the free edges of the leaves of the folded sheet are constituted as leading edges. 1

The present invention provides that the downward or rearward stroke of the gripper arm feeds the sheet between a pair of movable surfaces of an endless conveyor device, e.g. a pair of conveyorrollers or bands, which deliver the folded sheet to a spreading arrangement and/or transport chain as previously described. 1

Since the drum is horizontaL'th'e forward stroke of the gripper tool (located at the f rst quadrantof the drum path), is

upward to draw the sheet away from the destacking drum which preferably has a discharge station at a descending part of the rotation path of this drum, 1

According to a further feature of this invention, means is provided for adjusting the stroke of theswingable gripper upper extremepositions of this gripper lever. in this manner,

the apparatus can be readily adjusted todestack sheets of varying width using a conventionaldestacking drum and couning the drum or the rollers thereof. 1

terrotating rollers angularly spacedthe'reabout without chang- In fact, the adjustable gripper lever allows an accommodation of the device to folded sheets of different width without modification of the remainder of the device. The distance between the conveyor means and the point at which the sheet is discharged from the destacking drum can, moreover, be minimum, e.g. a distance corresponding to the width of the narrowest folded sheet to be processed. When signatures of greater width are to be processed, a corresponding adjustment of the angle of oscillation of the gripper lever is effected ,so that this lever carries the folded edge of the signature higher as the width of the signature is greater.

According to still another feature of this invention, the gripper lever is controlled by a cam arrangement coupled with the destacking drum and preferably including a cam mounted on the drum shaft and provided with a plurality of angularly equispaced cam formations corresponding in number to the pickup rollers of the drum. The gripper lever is provided with a double-arm lever fulcrumed at a fixed location upon the support from the drum and having a cam follower roller bearing against the periphery of the cam. The other arm is formed with a plurality of bores with which a connecting rod may be pivotally linked via a removable pin to drive the gripper lever. The latter maybe swingably mounted on the support and articulated with the connecting rod at a location close to the fulcrum of the gripper lever, preferably at an eccentric disc or shaft whereby the articulation is constituted by a pin eccentrically tied to this disc.

The above and other objects, features and advantages of the present inventionwill become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a schematic end view,.with the fold support plate removed, of a destacking drum and gripper lever arrangement according to the present invention, the conveyors being omitted from this FIG. for convenience of representation;

FIG. 2 is a diagrammatic view similar to FIG. 1, showing the parts of the assembly in other positions corresponding to an intermediate phase in the operation;

FIG. 3 is another view similar to FIGS. 1 and 2, illustrating the mechanism in which the signature has been transferred to the conveyor device;

FIG. 4 is a detail view, partly in diagrammatic form, of a control system for the gripper lever or arm shown in FIGS. 1-

FIG. 5 is a plan view of the device diagrammatically representing the lever, the cam mechanism and the remainder of the destacking systems; and

FIGS. 6A6E are diagrams showing the various positions of the gripper lever or arm in accordance with the present invention.

From FIGS. l3 and 5, it can be seen that a destacking assembly according to the present invention can comprise a pair of support plates disposed at opposite ends of a destacking drum or cylinder support 1 which is mounted upon a shaft 2 and driven by means not shown.

The drum 1, in turn, comprises a pair of end plates la and lb spanned by three angularly equispaced arrays of guide bars 21, 22 and 23, the bars 24 ofeach array defining the periphery of the drum and extending parallel to the axis A of rotation thereof. The bars 24 lie along generatrices of a cylinder centered on the axis A and thus form an arcuate guide preventing the sheets from falling into the interior of the drum. In general, the drum may be constructed, driven and arranged as described in my application Ser. No. 690,445 mentioned earli- The drum 1 is rotatable in the clockwise sense (FIGS. 1- 3 as shown by the arrow B, and also includes three angularly equispaced pickup rollers 3a, 3b and 3c accessible in the gaps between the arrays 21-23 of bars 24. The pickup rollers 3a'-3c are rotated in a sense opposite that a drum 1 (Le. counterclockwise as shown by arrows C) about shafts which are represented at 4 as described in application Ser. No. 690,445 and my prior patents relating to such destacking and sheet feeder arrangements. Each of the pickup rollers 3a3c is provided with sheet-engaging means, preferably -in the form of a suction gripper 7 which is activated in accordance with the position of the roller and the drum to allow the roller to engage the sheets 6 of the stack 5.

Above the drum 1, I provide a set of guide rails,25 with hook-shaped lower extremities 26 against which the folded sheets or signatures 6 are stacked at 5 such that their foldslie against the rails 25 and are held in position by the hooks 26a The apparatus for destacking theisheets 6 also includes a gripper lever 8 which is swingably mounted on a shaft 9 between the plates 20 to move the gripper head 10 between a position in which this head engages the fold of a released sheet (FIG. 1) and a position in which the gripper I0 is elevated above the sheet release location represented at L in an upper limiting position U (FIG. 2). I

The mechanism for displacing the lever 8 is represented in FIG. 4 and comprises a disc-shaped sleeve 17 keyed to the shaft 9 and eccentrically connected at 27 to a connecting rod. 18. The latter is, in turn, pivotally connected to a double-arm. lever 14, fulcrumed (about a pivot axis parallel to the axes of.

shafts 2 and 9) at an intermediate location 16 to ohe of the plates 20 (bottom of FIG. 5) outwardly of the space defined between these plates. g

The free arm 15 of lever 14 is formed with a'plurality of holes 19 lying along an are substantially centered on the articulation point 27. In these holes 1 9,the connecting rod 18 may be detachably hinged to the arm 15, by a removable pintle 28. At its other arm, the lever 14 is provided with a cam follower roller 29 bearing against a cam 131mounted on the drum shaft 2 and rotatable therewith in the direction of arrow The cam 13 is provided with three angularly equispaced' formations 13a designed to synchronously displace the rod'l8' with movement ofthe drum. g L g Referring now to FIG. 6A, it can be seen that the arm 8 may be one of a number of arms (or all of them collectively) mounted in common upon a shaft 9 and provided with'cou'nterweights 30 remote from the gripper heads 10. The latter may include anvils 10a cooperating with gripper finger 10b between which the folded edge F of a sheet 6 may be clamped. As can best be seen from FIGS. 6A6E, means (e.g. pneu-. matic cylinder 40) may be-connected with the gripper fingers 10 to swing them about the pivot 41' in a clockwise sense to release the folded sheet 6 (FIG. 6D) and counterclockwise to clamp the folded sheet (FIGS. 6A6C). In these FIGS, the

fold of the sheet 6 represented at F can be seen engaged in the gripper 10, 10a, 10b after commencement of the upward stroke of the gripper lever 8 (FIG. 6a) which moves to an extreme upward position determined by the bore 19 of the lever 14 which has been selected as described earlier. This upper limiting position is shown in FIG. 6B. Thereafter, the cam I3 swings the lever 8 downwardly (counterclockwise in FIG. 6C) while the sheet 6 remains clamped in the gripper. At a point at which the free ends of the folded sheet 6 (represented at FF. in FIG. 3) is engaged between the conveyors the gripper 10 is opened to release the fold F of the sheet 6 (FIG. 6D) which continues its downward movement (FIG. 6E) until the gripper 10 is again in position to receive the fold F of a sheet 6.

The relationship of the rotation of the drum 1 to the gripper lever 6 is shown in FIGS. l3. In FIG. 1, the stack 5 is shown to be supported upon the grate formed by the rod array 23 while roller 3a has a gripper 7a engaging the folded edge of the underlying sheet 6 of the stack. The previously removed. folded sheet 6 has just been released by the gripper 7b of the:

roller 3b and engaged by the gripper 10 of lever 8 at the release location L. As the drum 1 continues its clockwise rotation and the roller 3b continues its counterclockwise rotation (FIG. 1), the sheet 6 is drawn upwardly (arrow U) by the lever 8 and rides along the array 23 of bars 24. Below the release location L, there is positioned a conveyor means in the form of a band-type conveyor in which a pair of sets of endless bands I I r From FIG. 2, it can be seen that the sheet 6 is wound upon the roller 3a while roller 30 is advanced into position beneath the stack 5 and roller 3b has fully paid off the preceding sheet 6 which is drawn upwardly by the gripper lever 8. As rotation of the drum 1 continues (FIG. 3), the bands 11 and 12, which may be driven by a programming motor, not shown, are operated to accept the free ends FE of the sheet 6 while the next sheet 6 is brought to the discharge location by the roller 3a, the sheet 6 riding downwardly against the bars of the array 23 The sheets 6, 6, etc. are then deposited on a fold-spreading conveyor as represented at 50. The suction devices 7, 7a and 7b, the gripper actuating means 40 andthe bands 11 and 12 may be programmed in synchronism with the shaft 2 as described in the aforementioned copending application and my earlier patents relating to destacking collating and signature-forming apparatus. The intake side of the path P is located below the location L at a distance therefrom corresponding to the minimum width, in the direction of rotation of the drum 1, of

ls qshse lai 1. An apparatus for destacking successive folded sheets from a stack thereof wherein the folded sheets have fold edges located at one side of said stack and free edges located at the opposite side of the stack, said apparatus comprising:

a rotatable destacking drum rotatablebeneath said stack and provided with a plurality of angularly spaced rollers rotatable in a sense opposite the sense of rotation of said drum, said rollers each being provided with means adapted to entrain the fold edges of successively lowermost sheets of said stack upon rotation of said drum therepast to carry the respective sheets to a release location angularly offset from said stack about the axis of said drum; a

conveyor means spaced from said location in the sense of rotation of said drum for displacement of said sheets along a predetermined transport path;

reversibly swingable gripper means adjacent said drum for engagement with the fold edges of the successive sheets delivered to said location to draw each folded sheet by its fold edge away from said location in a direction counter to the direction of rotation of said drum and thereafter shift each sheet generally in the direction of rotation of said drum to said conveyor means whereby said conveyor means entrains the successive sheets by their free ends, said reversibly swingable gripper means including a gripper arm formed with a gripper head releasably engageable with the fold edges of said sheets;'

a pivot swingably mounting said'arm for oscillating movement about an axis parallel to and above the axis of said drum; and

control means operatively connecting said arm with said drum and including means for adjusting the stroke of said arm to accommodate sheets of different width.

2. The apparatus defined in claim-l wherein said control means includes a rocker lever pivotal about a fulcrum parallel to said axis, and a connecting rod interconnecting said arm and said lever, said connecting rod and said lever beingprovided with means enabling the articulated connection of said arm at selected distances from said fulcrum.

3. The apparatus defined in claim 2 wherein said drum is provided with a shaft, said control means further comprising a formed with arrays of guide bars parallel to said axis between each two of said rollers.

6. The apparatus defined in claim 5 wherein said head is provided with gripper fingers releasably engageable with said fold ed es of said sheets. I

7. T e apparatus defined in claim 6 wherein the means on said rollers adapted to entrain the fold edges of the successive sheets includes a suction device.

8. An apparatus for destacking successive folded sheets from a stack thereof wherein the foldedsheets have fold edges located at one side of said stack and free edges located at the opposite side of the stack, said apparatus comprising:

a rotatable destacking drum rotatable beneath said stack and provided with a plurality of angularly spaced rollers rotatable in a sense opposite the sense of rotation of said drum, said rollers each being provided with means adapted'to entrain the fold edges of successively lowermost sheets of said stack upon rotation of said drum therepast to carry the respective sheets to a release location angularly offset from said stack about the axis of said drum; conveyor means spaced from said location in the sense of rotation of said drum for displacement of said sheets along a predetermined transport path; and reversible swingable gripper means adjacent said drum for engagement with the fold edges of the successive sheets delivered to said location to draw each folded sheet by its fold edge away from said location in a direction counter to the direction of rotation of said drum and thereafter shift each sheet generally in the direction of rotation of said drum to said conveyor means whereby said conveyor means entrains the successive sheets by their free ends, said reversibly swingable gripper means including: a gripper arm formed with a gripper head releasably engageablewith the fold edges of said sheets; and a pivot swingably mounting said arm for oscillating movement about an axis parallel to and above the axis of said drum, said conveyor and gripper means being positioned to guide said sheet along said drum generally tangential thereto during displacement of said sheet in said direction of rotation of said drum. 

1. An apparatus for destacking successive folded sheets from a stack thereof wherein the folded sheets have fold edges located at one side of saId stack and free edges located at the opposite side of the stack, said apparatus comprising: a rotatable destacking drum rotatable beneath said stack and provided with a plurality of angularly spaced rollers rotatable in a sense opposite the sense of rotation of said drum, said rollers each being provided with means adapted to entrain the fold edges of successively lowermost sheets of said stack upon rotation of said drum therepast to carry the respective sheets to a release location angularly offset from said stack about the axis of said drum; conveyor means spaced from said location in the sense of rotation of said drum for displacement of said sheets along a predetermined transport path; reversibly swingable gripper means adjacent said drum for engagement with the fold edges of the successive sheets delivered to said location to draw each folded sheet by its fold edge away from said location in a direction counter to the direction of rotation of said drum and thereafter shift each sheet generally in the direction of rotation of said drum to said conveyor means whereby said conveyor means entrains the successive sheets by their free ends, said reversibly swingable gripper means including a gripper arm formed with a gripper head releasably engageable with the fold edges of said sheets; a pivot swingably mounting said arm for oscillating movement about an axis parallel to and above the axis of said drum; and control means operatively connecting said arm with said drum and including means for adjusting the stroke of said arm to accommodate sheets of different width.
 2. The apparatus defined in claim 1 wherein said control means includes a rocker lever pivotal about a fulcrum parallel to said axis, and a connecting rod interconnecting said arm and said lever, said connecting rod and said lever being provided with means enabling the articulated connection of said arm at selected distances from said fulcrum.
 3. The apparatus defined in claim 2 wherein said drum is provided with a shaft, said control means further comprising a cam mounted on said shaft and cam follower means on said lever engaging said cam, said cam being formed with a plurality of cam formations corresponding in number to the number of said rollers on said drum.
 4. The apparatus defined in claim 3 wherein said conveyor means includes a pair of endless conveyors defining a transport path generally tangential to said drum and receiving said free ends of said sheets between them.
 5. The apparatus defined in claim 4 wherein said drum is formed with arrays of guide bars parallel to said axis between each two of said rollers.
 6. The apparatus defined in claim 5 wherein said head is provided with gripper fingers releasably engageable with said fold edges of said sheets.
 7. The apparatus defined in claim 6 wherein the means on said rollers adapted to entrain the fold edges of the successive sheets includes a suction device.
 8. An apparatus for destacking successive folded sheets from a stack thereof wherein the folded sheets have fold edges located at one side of said stack and free edges located at the opposite side of the stack, said apparatus comprising: a rotatable destacking drum rotatable beneath said stack and provided with a plurality of angularly spaced rollers rotatable in a sense opposite the sense of rotation of said drum, said rollers each being provided with means adapted to entrain the fold edges of successively lowermost sheets of said stack upon rotation of said drum therepast to carry the respective sheets to a release location angularly offset from said stack about the axis of said drum; conveyor means spaced from said location in the sense of rotation of said drum for displacement of said sheets along a predetermined transport path; and reversible swingable gripper means adjacent said drum for engagement with the fold edges of the successive sheets delivered to said location to draw each folded sheet by its fold edge away from said location In a direction counter to the direction of rotation of said drum and thereafter shift each sheet generally in the direction of rotation of said drum to said conveyor means whereby said conveyor means entrains the successive sheets by their free ends, said reversibly swingable gripper means including: a gripper arm formed with a gripper head releasably engageable with the fold edges of said sheets; and a pivot swingably mounting said arm for oscillating movement about an axis parallel to and above the axis of said drum, said conveyor and gripper means being positioned to guide said sheet along said drum generally tangential thereto during displacement of said sheet in said direction of rotation of said drum. 